Identification and Clinical Validation of Biomarkers Associated With Clinical Severity in Adults Infected With RSV

A short description, 5000 characters Intro: Respiratory Syncytial Virus (RSV) is a frequent, ubiquitous agent of respiratory viral infections. It is the leading viral cause of lower respiratory tract infection (LRTI) in infants and also causes significant morbidity and mortality in adults, especially in the elderly, in patients with cardiorespiratory comorbidities \[e.g., patients with Chronic Obstructive Pulmonary Disease (COPD) and/or heart failure\], and in immunocompromised patients. Clinical phenotyping of RSV respiratory infections has shown that the occurrence of LRTI in RSV-infected patients is associated with the need for ventilatory support and an increased risk of mortality. Virological data also suggest that there is a relationship between high nasopharyngeal viral replication levels and a poor prognosis, although these data have not been confirmed in other studies. Beyond viral load, the impact of viral subtypes on the severity of RSV infection is controversial. Few data have explored the prognostic value of genetic diversity (i.e., role of RSV variants, mutations occurring during clinical course) in RSV-infected adult patients with acute respiratory failure. Objective: The main goal of the present study is to identify and validate biomarkers associated with RSV severity in adults infected with RSV that will be useful to guide treatment decisions in the future. This study will additionally characterize the thus far unknown genetic diversity of RSV in hospitalized adults with severe and mild infections, in order to anticipate virological escape mechanisms from current and future treatments. Method: This is a prospective multicenter cohort study of patients with RSV infection admitted to the hospital. These patients will be followed-up for 28 days. Nasopharyngeal samples will be obtained sequentially (i.e., at day 0, day 3-4, day 5-7, and day 14 of inclusion) for virological and transcriptomic analyses. Blood samples will also be collected at day 0 (EDT